Treatment or renovation of foundry-sand.



on rrE sTAtrns PATENT OFFICE.

ANDREW ZPOULSON, 0F FARNWORTH, WIDNES, ENGLAND.

' TREATMENT ORG RENOVATION OF FOUNDRY-SAND.

vate spent foundry sand by adding thereto sulfate of alumina solely or in combination with {chloride of calcium, sodium,.magnesit-1m; or other chlorids. It has also been proposed to use ge atinous silica in the renovation of foundry sand for green sand molding, thesulfate of alumina when used solely or in combination with chlorids 'being adapted for the treatment of sand used ini'd'ry sand molding, the making of cores, anfd loaiii molding. It is found, however, in the case} of foundry sand treated with chlorids that the molds or cores have a distinct afiinity: for moisture. This is particularly noticeable where the sand has been treated with ohlorid of magnesium. In consequence of this affinity for moisture, the surface of the core is liahleto become soft, the castings produced in the molds, developingv blow holes or pelleting. I

manner referred to, magnesite, pure magnesia, or any other-suitable compounds of magnesia, exclusive of chlorid .of magnesium, which shall have the effect of renderabout equal parts of'snlfate of magnesia and sulfate of alumina, to which Ininture wateris added, suitable proportions being, sulfate of magnesia four ounces, sulfate of alumina Specification of Letters Patent. Application filed June 2, 1913.

Patented Nov. 11, 1913. Serial No. 771,260.

four ounces, and water four ounces. For loam molding I prefer to take about equal parts of carbonate of magnesia and sulfate ofalumina to which water is added in asimilar manner and proportion. The mixtures of sulfate of alumina and Water with v either sulfate of magnesia or carbonate of magnesia, according to the particular requirements, produce a paste or semi-paste, which is diluted as required and incorporated With the sand to be renovated in the proportion of say 3% lbs; of the paste mixture to one hundredweight of the sand to be 2; treated. This is the proportion I have 3- found to' give-satisfactory results in the laboratory, but for practical purposes aless proportion of paste might be used. The addition of sulfate of alumina to foundrysand acts to impart'or restore cohesive properties therein, and it is found that the addition ofthe paste or sc-nii paste, which contains sul.-'

fate of magnesia or carbonate of magnesia according to the particular molding use for which the innovator sand is prepared, acts to renderfitho sand moisture proof when made up in the mold'or as cores In the utilization of this process with the gelatinous silica treatment for green sand, the paste may be made more diluteor thinner than is required when treating foundr sand for the purpose of dry sand moldin making cores, or loam work.

I claim i .A process for the treatment or renovation of foundry sand which consists in adding to the sand equal parts by weight of sulfate of alumina,-sulfate of magnesia. and Water. "In testimony whereof I affiX. my: signature in presence oftwo witnesses.

ANDnEw' ouLsoN;

Witnesses:

. A; J.-'Davms, WVILLIAnS; 

